This application claims priority to French Application No. 0107445 filed on Jun. 7, 2001, the entire contents of which are incorporated by reference herein.
The present invention relates to improvements made to devices for removably attaching an oar to the edge of a boat, comprising an oarlock attached to said boat edge and a coupling member, attached to the shaft of the oar, for the removable attachment thereof to the oarlock; the invention is aimed in particular, although not exclusively, at such devices designed to equip inflatable boats.
Numerous examples of devices of the aforementioned kind are already known.
For example, document FR-A-2 754 237 recites such a device, for an inflatable boat, which is simple in structure and inexpensive (component parts few in number and which can be made of plastic), which is easy to use and which has no dangerous angular components.
However, this known device has the disadvantage that the oar presses only in one direction, that is to say that the thole pin presses against the oarlock only if the oar is subjected to a force directed outward (which, in principle, it is during use). However, there is no means of retention if the oar is subjected to a force directed toward the inside of the boat and the thole pin then disengages from the oarlock.
Another disadvantage of this known device lies in the fact that there is just one axis of rotation of the oar, namely the vertical axis of rotation of the thole pin about the retaining knob provided on the oarlock. By contrast, there is no concrete horizontal axis of rotation of the oar, and vertical travel of the oar can be obtained only by providing a very significant amount of vertical play between the oarlock retaining knob and the elongate slot in the thole pin that cooperates with said retaining knob.
The known device described in that document is thus not able to offer optimum rowing conditions.
The main object of the invention is to propose a device for securing an oar to the edge of a boat which is better able to meet the requirements of the users and which, while remaining simple in structure, inexpensive and non-aggressive, affords effective and reliable attachment of the oar capable of facilitating use while at the same allowing it to be fitted and removed without any difficulty.
To these ends, an oar attachment device as recited in the preamble part is one, arranged according to the invention, wherein:
a) the oarlock comprises
a base arranged to be secured to said edge of the boat,
a transverse pivoting arm supported on said base by a spindle substantially parallel to said edge of the boat so as to be capable of pivoting freely with a predetermined angular amplitude, said arm having a cylindrical housing opening into its front end,
and locking means associated with said cylindrical housing and able to have, to the rear of the orifice of said housing and along the axis thereof, selectively a section provided with a hole of the same diameter as the housing and a section equipped with a hole of a smaller diameter,
and
b) a pivot secured to the shaft of the oar and projecting substantially radially from the latter, said pivot having a diameter substantially equal to that of said housing of the pivoting arm and being hollowed by an annular groove of smaller diameter substantially equal to that of the smaller-diameter hole of the locking means.
Advantageously, to form the locking means:
the arm is arranged in hollow shape with an interior cavity,
the arm has a lateral orifice in communication with said interior cavity, and
the locking means comprise a sliding plunger, particularly in the form of a plate, engaged through said lateral orifice, protruding partially therefrom, on one side, and extending across said housing, on the other side, said plunger comprising said hole having substantially the same diameter as the housing and said hole of smaller diameter arranged one after the other in the direction in which said plunger slides, said both holes being partially secant and forming a single opening in the overall shape of an asymmetric 8.
In a preferred embodiment, the locking means comprise elastic return means able to return the plunger to a position of rest for which it is the smaller-diameter hole which is placed coaxially with said housing; and then, for preference, the elastic return means comprise at least one spring housed in said interior cavity of the arm and pressing against the plunger and, in one concrete exemplary embodiment, the spring may consist of a rigid strip of elastically deformable material, with one end secured to the plunger and with its other end anchored in the cavity; and then, in a simple way, the plunger and the elastically deformable strip forming the spring are formed integrally as one single piece; in a compact embodiment, the anchoring region of the strip is wound into an arc of a circle about the spindle of the pivoting arm, to which it is attached with preload, so as to generate the elastic return force returning the plunger.
To make it easier to fit the oar, it is conceivable for the free end of the pivot secured to the shaft of the oar to be shaped in an approximately conical or frustoconical shape: all that is then required is for the pivot to be pushed into the housing of the arm to snap-fasten it and axially retain it.
The pivot secured to the oar may be a component pushed directly radially into the shaft of the oar. However, in a preferred embodiment, the pivot secured to the shaft of the oar belongs to a thole pin comprising a ring able to grip firmly around the shaft of the oar, said pivot being secured to said ring approximately radially; in this case, provision may advantageously be made for the ring of the thole pin to be of oblong shape with a short transverse dimension appreciably smaller than the transverse dimension of the shaft of the oar.
Due to features according to the invention, not only a simple device having only a minimum number of component parts which are simple to manufacture is formed, but the pivot of the oar is also secured effectively and efficiently in both directions in the oarlock while at the same time forming a double rotary articulation, about two mutually orthogonal axes, of the oar with respect to the base of the oarlock. What is more, the oar is particularly simple and quick to fit into the oarlock or remove therefrom.
Such a device may find a preferred application in equipping inflatable boats, by virtue of the base being shaped in such a way that it can be secured to the inflatable buoyancy fender of the boat.